// Gmsh - Copyright (C) 1997-2019 C. Geuzaine, J.-F. Remacle
//
// See the LICENSE.txt file for license information. Please report all
// issues on https://gitlab.onelab.info/gmsh/gmsh/issues.

#include <set>
#include "GmshConfig.h"
#include "GModel.h"
#include "MLine.h"
#include "MTriangle.h"
#include "MQuadrangle.h"
#include "ExtrudeParams.h"
#include "MVertexRTree.h"
#include "Context.h"
#include "GmshMessage.h"

#if defined(HAVE_QUADTRI)
#include "QuadTriExtruded2D.h"
#endif

static void addTriangle(MVertex *v1, MVertex *v2, MVertex *v3, GFace *to)
{
    to->triangles.push_back(new MTriangle(v1, v2, v3));
}

static void addQuadrangle(MVertex *v1, MVertex *v2, MVertex *v3, MVertex *v4,
                          GFace *to)
{
    to->quadrangles.push_back(new MQuadrangle(v1, v2, v3, v4));
}

static void
createQuaTri(std::vector<MVertex *> &v, GFace *to,
             std::set<std::pair<MVertex *, MVertex *> > *constrainedEdges,
             MLine *source, int tri_quad_flag)
{
    ExtrudeParams *ep = to->meshAttributes.extrude;
    if(v[0] == v[1] || v[1] == v[3])
        addTriangle(v[0], v[3], v[2], to);
    else if(v[0] == v[2] || v[2] == v[3])
        addTriangle(v[0], v[1], v[3], to);
    else if(v[0] == v[3] || v[1] == v[2])
        Msg::Error("Uncoherent extruded quadrangle in surface %d", to->tag());
    else {
        // Trevor Strickler added the tri_quad_flag stuff here.
        if((ep->mesh.Recombine && tri_quad_flag != 2) || tri_quad_flag == 1) {
            if(!constrainedEdges)
                addQuadrangle(v[0], v[1], v[3], v[2], to);
            else {
                std::pair<MVertex *, MVertex *> p1(std::min(v[1], v[2]),
                        std::max(v[1], v[2]));
                std::pair<MVertex *, MVertex *> p2(std::min(v[0], v[3]),
                        std::max(v[0], v[3]));
                if(constrainedEdges->count(p1)) {
                    addTriangle(v[2], v[1], v[0], to);
                    addTriangle(v[2], v[3], v[1], to);
                }
                else if(constrainedEdges->count(p2)) {
                    addTriangle(v[2], v[3], v[0], to);
                    addTriangle(v[0], v[3], v[1], to);
                }
                else
                    addQuadrangle(v[0], v[1], v[3], v[2], to);
            }
        }
        else if(!constrainedEdges) {
            addTriangle(v[0], v[1], v[3], to);
            addTriangle(v[0], v[3], v[2], to);
        }
        else {
            std::pair<MVertex *, MVertex *> p(std::min(v[1], v[2]),
                    std::max(v[1], v[2]));
            if(constrainedEdges->count(p)) {
                addTriangle(v[2], v[1], v[0], to);
                addTriangle(v[2], v[3], v[1], to);
            }
            else {
                addTriangle(v[2], v[3], v[0], to);
                addTriangle(v[0], v[3], v[1], to);
            }
        }
    }
}

static void
extrudeMesh(GEdge *from, GFace *to, MVertexRTree &pos,
            std::set<std::pair<MVertex *, MVertex *> > *constrainedEdges)
{
    ExtrudeParams *ep = to->meshAttributes.extrude;

    // create vertices (if the edges are constrained, they already exist)
    if(!constrainedEdges) {
        for(std::size_t i = 0; i < from->mesh_vertices.size(); i++) {
            std::vector<MVertex *> extruded_vertices;
            MVertex *v = from->mesh_vertices[i];
            MEdgeVertex *mv = (MEdgeVertex *)v;
            mv->bl_data = new MVertexBoundaryLayerData();
            for(int j = 0; j < ep->mesh.NbLayer; j++) {
                for(int k = 0; k < ep->mesh.NbElmLayer[j]; k++) {
                    double x = v->x(), y = v->y(), z = v->z();
                    ep->Extrude(j, k + 1, x, y, z);
                    if(j != ep->mesh.NbLayer - 1 || k != ep->mesh.NbElmLayer[j] - 1) {
                        MVertex *newv = 0;
                        if(to->geomType() != GEntity::DiscreteSurface &&
                                to->geomType() != GEntity::BoundaryLayerSurface) {
                            SPoint3 xyz(x, y, z);
                            SPoint2 uv = to->parFromPoint(xyz);
                            newv = new MFaceVertex(x, y, z, to, uv[0], uv[1]);
                        }
                        else {
                            newv = new MVertex(x, y, z, to);
                        }
                        to->mesh_vertices.push_back(newv);
                        pos.insert(newv);
                        extruded_vertices.push_back(newv);
                    }
                }
            }
            mv->bl_data->addChildrenFamily(extruded_vertices);
        }
    }

    int tri_quad_flag = 0;

#if defined(HAVE_QUADTRI)
    // figure out whether to recombine this surface or not in the event of
    // quadToTri region neighbors (if QuadToTri, tri_quad_flag is an int flag that
    // lets createQuadTri() override the surface's intrinsic ep->mesh.Recombine
    // flag.  tri_quad_flag values: 0 = no override, 1 = mesh with quads, 2 = mesh
    // with triangles.)
    bool detectQuadToTriLateral = false;
    bool quadToTri_valid =
            IsValidQuadToTriLateral(to, &tri_quad_flag, &detectQuadToTriLateral);
    if(detectQuadToTriLateral && !quadToTri_valid)
        Msg::Error(
                    "In MeshGFaceExtrudedSurface::extrudeMesh(), Mesh of QuadToTri Lateral "
                    "surface %d likely has errors.",
                    to->tag());
#endif

    // create elements (note that it would be faster to access the *interior*
    // nodes by direct indexing, but it's just simpler to query everything by
    // position)
    for(std::size_t i = 0; i < from->lines.size(); i++) {
        MVertex *v0 = from->lines[i]->getVertex(0);
        MVertex *v1 = from->lines[i]->getVertex(1);
        for(int j = 0; j < ep->mesh.NbLayer; j++) {
            for(int k = 0; k < ep->mesh.NbElmLayer[j]; k++) {
                std::vector<MVertex *> verts;
                double x[4] = {v0->x(), v1->x(), v0->x(), v1->x()};
                double y[4] = {v0->y(), v1->y(), v0->y(), v1->y()};
                double z[4] = {v0->z(), v1->z(), v0->z(), v1->z()};
                for(int p = 0; p < 2; p++) {
                    ep->Extrude(j, k, x[p], y[p], z[p]);
                    ep->Extrude(j, k + 1, x[p + 2], y[p + 2], z[p + 2]);
                }
                for(int p = 0; p < 4; p++) {
                    MVertex *tmp = pos.find(x[p], y[p], z[p]);
                    if(!tmp) {
                        Msg::Error("Could not find extruded vertex (%.16g, %.16g, %.16g) "
                                   "in surface %d",
                                   x[p], y[p], z[p], to->tag());
                        return;
                    }
                    verts.push_back(tmp);
                }
                createQuaTri(verts, to, constrainedEdges, from->lines[i],
                             tri_quad_flag);
            }
        }
    }
}

static void copyMesh(GFace *from, GFace *to, MVertexRTree &pos)
{
    ExtrudeParams *ep = to->meshAttributes.extrude;

    // interior vertices
    std::vector<MVertex *> mesh_vertices = from->mesh_vertices;

    // add all embedded vertices
    std::vector<MVertex *> embedded = from->getEmbeddedMeshVertices();
    mesh_vertices.insert(mesh_vertices.end(), embedded.begin(), embedded.end());

    // create extruded vertices
    for(std::size_t i = 0; i < mesh_vertices.size(); i++) {
        MVertex *v = mesh_vertices[i];
        double x = v->x(), y = v->y(), z = v->z();
        ep->Extrude(ep->mesh.NbLayer - 1, ep->mesh.NbElmLayer[ep->mesh.NbLayer - 1],
                x, y, z);
        MVertex *newv = 0;
        if(to->geomType() != GEntity::DiscreteSurface &&
                to->geomType() != GEntity::BoundaryLayerSurface) {
            SPoint3 xyz(x, y, z);
            SPoint2 uv = to->parFromPoint(xyz);
            newv = new MFaceVertex(x, y, z, to, uv[0], uv[1]);
        }
        else {
            newv = new MVertex(x, y, z, to);
        }
        to->mesh_vertices.push_back(newv);
        to->correspondingVertices[newv] = v;
        pos.insert(newv);
    }

    std::vector<double> tfo;
    //ep->GetAffineTransform(tfo); // TODO: check transform
    to->GEntity::setMeshMaster(from, tfo, false);

#if defined(HAVE_QUADTRI)
    // if performing QuadToTri mesh, cannot simply copy the mesh from the source.
    // The vertices and triangles can be copied directly though.  First, of
    // course, do some checks and make sure this is a valid QuadToTri top surface
    // before engaging in QuadToTri meshing.
    int quadToTri = NO_QUADTRI;
    bool detectQuadToTriTop = false;
    int quadToTri_valid =
            IsValidQuadToTriTop(to, &quadToTri, &detectQuadToTriTop);
    bool is_toroidal = quadToTri_valid >= 2 ? true : false;
    bool is_noaddverts = quadToTri_valid == 3 ? true : false;
    if(detectQuadToTriTop && !quadToTri_valid && !is_toroidal) {
        Msg::Error("In MeshGFaceExtrudedSurface::copyMesh(), Mesh of QuadToTri top "
                   "surface %d likely has errors.",
                   to->tag());
    }

    // if this is toroidal No New Vertices QuadToTri, then replace the root
    // dependency face's boundary quads with triangles for better meshing.
    if(is_toroidal && is_noaddverts) {
        GFace *root = findRootSourceFaceForFace(from);
        if(root == from) {
            ReplaceBndQuadsInFace(root);
            Msg::Warning(
                        "To facilitate QuadToTri interface on surface %d, source "
                        "surface %d was re-meshed with all triangles on boundary. "
                        "To avoid this, use QuadTriAddVerts instead of QuadTriNoNewVerts",
                        to->tag(), root->tag());
        }
    }
#endif

    // create triangle elements
    for(std::size_t i = 0; i < from->triangles.size(); i++) {
        std::vector<MVertex *> verts;
        for(int j = 0; j < 3; j++) {
            MVertex *v = from->triangles[i]->getVertex(j);
            double x = v->x(), y = v->y(), z = v->z();
            ep->Extrude(ep->mesh.NbLayer - 1,
                        ep->mesh.NbElmLayer[ep->mesh.NbLayer - 1], x, y, z);
            MVertex *tmp = pos.find(x, y, z);
            if(!tmp) {
                Msg::Error(
                            "Could not find extruded vertex (%.16g, %.16g, %.16g) in surface %d",
                            x, y, z, to->tag());
                return;
            }
            verts.push_back(tmp);
        }
        addTriangle(verts[0], verts[1], verts[2], to);
    }

#if defined(HAVE_QUADTRI)
    // Add triangles for divided quads for QuadTri. If quadtotri and not part of a
    // toroidal extrusion, mesh the top surface accordingly
    if(detectQuadToTriTop && !is_toroidal) {
        if(!MeshQuadToTriTopSurface(from, to, pos))
            Msg::Error("In MeshExtrudedSurface()::copyMesh(), mesh of QuadToTri top "
                       "surface %d failed.",
                       to->tag());
        return;
    }
#endif

    // create quadrangle elements if NOT QuadToTri and NOT toroidal
    for(std::size_t i = 0; i < from->quadrangles.size(); i++) {
        std::vector<MVertex *> verts;
        for(int j = 0; j < 4; j++) {
            MVertex *v = from->quadrangles[i]->getVertex(j);
            double x = v->x(), y = v->y(), z = v->z();
            ep->Extrude(ep->mesh.NbLayer - 1,
                        ep->mesh.NbElmLayer[ep->mesh.NbLayer - 1], x, y, z);
            MVertex *tmp = pos.find(x, y, z);
            if(!tmp) {
                Msg::Error(
                            "Could not find extruded vertex (%.16g, %.16g, %.16g) in surface %d",
                            x, y, z, to->tag());
                return;
            }
            verts.push_back(tmp);
        }
        addQuadrangle(verts[0], verts[1], verts[2], verts[3], to);
    }
}

int MeshExtrudedSurface(
        GFace *gf, std::set<std::pair<MVertex *, MVertex *> > *constrainedEdges)
{
    ExtrudeParams *ep = gf->meshAttributes.extrude;

    if(!ep || !ep->mesh.ExtrudeMesh) return 0;

    Msg::Info("Meshing surface %d (extruded)", gf->tag());

    // build an rtree with all the vertices on the boundary of the face gf
    MVertexRTree pos(CTX::instance()->geom.tolerance * CTX::instance()->lc);
    std::vector<GEdge *> const &edges = gf->edges();
    std::vector<GEdge *>::const_iterator it = edges.begin();
    while(it != edges.end()) {
        pos.insert((*it)->mesh_vertices);
        if((*it)->getBeginVertex())
            pos.insert((*it)->getBeginVertex()->mesh_vertices);
        if((*it)->getEndVertex())
            pos.insert((*it)->getEndVertex()->mesh_vertices);
        ++it;
    }

    // if the edges of the mesh are constrained, the vertices already
    // exist on the face--so we add them to the set
    if(constrainedEdges) {
        pos.insert(gf->mesh_vertices);
    }

    if(ep->geo.Mode == EXTRUDED_ENTITY) {
        // surface is extruded from a curve
        GEdge *from = gf->model()->getEdgeByTag(std::abs(ep->geo.Source));
        if(!from) {
            Msg::Error("Unknown source curve %d for extrusion", ep->geo.Source);
            return 0;
        }
        extrudeMesh(from, gf, pos, constrainedEdges);
    }
    else {
        // surface is a copy of another surface (the "top" of the extrusion)
        GFace *from = gf->model()->getFaceByTag(std::abs(ep->geo.Source));
        if(!from) {
            Msg::Error("Unknown source surface %d for extrusion", ep->geo.Source);
            return 0;
        }
        else if(from->geomType() != GEntity::DiscreteSurface &&
                from->meshStatistics.status != GFace::DONE) {
            // cannot mesh the face yet (the source face is not meshed):
            // will do it later
            return 1;
        }
        copyMesh(from, gf, pos);
    }

    gf->meshStatistics.status = GFace::DONE;
    return 1;
}
